Aniline purification process

US10889539B2 · kind B2 · utility

Assignee

• Covestro Deutschland AG · DE

Inventors

• Michael Merkel · Hof, DE
• Friedhelm Steffens · Leverkusen, DE
• Murat Kalem · Neuss, DE
• Peter Lehner · Baytown, US

Key dates

• Filing date: Oct 16, 2019
• Grant date: Jan 12, 2021
• Expiry date: Oct 16, 2039

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C211/46
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

The present invention concerns a process for the preparation of pure aniline, comprising the steps of a) providing a crude aniline fraction containing up to 20.000% by weight of phenol; b) dividing the crude aniline fraction from step a) into a first partial stream and a second partial stream; c) distilling the first partial stream from step b) in a first distillation column and distilling the second partial stream from step b) in a second distillation column, wherein the first distillation column is operated at a higher head pressure than the second distillation column, with the proviso that each of the first distillation column and the second distillation column is operated at a head pressure in the range from 1.0 mbar(abs.) to 500 mbar(abs.), and wherein from each of the first distillation column and the second distillation column, (i) a gaseous aniline distillate (=purified aniline) is removed as the overhead product and subsequently condensed, wherein a first partial stream of the condensed aniline distillate is returned to the first and/or the second distillation column as a reflux stream and a second partial stream of the condensed aniline distillate is removed as the produc…